1. Field of the Invention
The present invention relates to a circuit that controls the potential of a gate of a switching element.
2. Description of Related Art
A circuit that controls the potential of a gate of IGBT is disclosed in International Publication WO2012/014314. This circuit has a pMOS and a resistor that are connected in series between the gate of the IGBT and a driving power supply. An operational amplifier is connected to a gate of the pMOS. The pMOS is controlled by the operational amplifier so that the pMOS can have a constant drain voltage. As a result, the potential of the gate of the IGBT is increased to a predetermined value.
In the technique that is disclosed in International Publication WO2012/014314, the rate of increase of the gate potential of the IGBT is determined by the slew rate of the operational amplifier. Because the slew rate considerably varies among operational amplifiers, the rate of increase of the gate potential of the IGBT varies among the gate potential control circuits of International Publication WO2012/014314.